|Colony of Colorful Sea Whips (Ellisella ceratophyta), Bunaken Island, Indonesia|
Despite its appearance, this is not a plant. It is a colony of Sea Whips -- a type of soft coral. This colorful species, Ellisella ceratophyta, occurs in many locations throughout the Indo-Pacific region. I photographed this example at Indonesia's Bunaken Island.
Sea Whips are Octocorals. That is, their polyps have eight tentacles. Like most Octocorals, they feed at night by extending their feathery tentacles to catch tiny bits of nutrients from the surrounding water. The colony pictured here was photographed in the daytime, so its polyps are completely retracted, giving the branches a smooth appearance.
To facilitate feeding, colonies of Sea Whips tend to establish themselves in places where there is a mild to moderate current. When the tentacles of the coral polyps are extended, they are able to catch particulates and tiny plankton carried along by the current.